lecture 16 cell biology
lecture 16 cell biology BIOL 225
Popular in Cell Biology
verified elite notetaker
Popular in Biology
verified elite notetaker
This 4 page Class Notes was uploaded by MelLem on Thursday April 28, 2016. The Class Notes belongs to BIOL 225 at Simmons College taught by Dr. Lopilato in Fall 2016. Since its upload, it has received 17 views. For similar materials see Cell Biology in Biology at Simmons College.
Reviews for lecture 16 cell biology
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/28/16
Cell Biology BIOL 225 Lecture 16 Interactions of Mammalian Cells with Extracellular Matrix • In culture • In the body • Components of the Extracellular matrix • Cell signaling • Focal Adhesions – contacts when the cell starts making contact. Allows cells to attach to the substratum ( Surface of a flask, cover slip) seen invitro • Invitro – in a lab, in class, tissue culture. • Normal human cells can not grown in a suspension (in liquid). Normal human cells require a surface to grow on. • Cancer cells however can grow in suspension, like a bacteria or yeast cell. How cells interact with their extracellular environment • Extracellular matrix – scaffolding, support for tissues o Fibrous for support • Connective tissue • Basement membrane underneath the plasma membrane (basement membrane does not contain cells. • Basement membrane prevents cancer cells from entering tissues. Components of the extracellular matrix • Integrins – integrated through the membrane • Integrin transmembrane proteins bind to components of the ECM in their active form. o Can transmit signals • Integrins transmit signals from ECM to cell interior • Collagen o Trip helix of 3 polypeptides (alpha) o Has a lot of prolines + lysines (get hydroxylated – adding OH – gives opportunity for hydrogen bonds) o Hydroxylated prolines and lysines form hydrogen bonds to join the three alpha polypeptides into a collagen fiber o 1mm fiber can hold 22 pounds (10 Kilograms) without breaking o For hydroxylation to occur, you need vitamin C (as a cofactor for hydroxylations) (ascorbic Acid) o Lack of vitamin C = Scurvy o Collagen associated Diseases ▯ Fibrosis of the lungs and liver (liver = cerosis) ▯ Type 1 defect – osteogenesis imperfect + fragile bones ▯ Type 4 – kidney disease – alport o Talin – adaptor protein that links integrins to the cytoskeleton • Proteoglycan • Fibronectin o Polypeptide o Held together by disulfide bonds o RGD – binding site for the integrins o Defects in fibronectin ▯ Development – cells must migrate and fibronectin directs their migration ▯ The lung and kidney develop from branching structure and need to form clefts. • Laminin • Changing in the ECM are conveyed by binding to our receptor and activates the kinases and causes changes in the cell. Hemidesmosomes Anchor Cells to ECM • Hemidesmosomes – anchor the cells to the ECM • Integrins – found only in animals, theres 18 different alphas an 8 different beta chains. Heterodimer. About 24 different integrins • You need integrins to interact with the basement membrane and the ECM tissues + substratum in tissue cultures. • Because of integrins, normal cells do not grow in suspension, you need substratum contact to generate signals for cell viability. • Hemidesmosomes – cant attach in some auto immune diseases to the basement membrane (causes severe blistering) • Defects in integrins, collagen or laminin 5 also disrupt the basement membrane Junctions for communication • Gap Junctions – animal cells o Connexin o Passage of ions • Plasmodesmata – plant cells o Connect plant cells o Dilates for passage of macromolecules • Plasmodesmata – cytoplasmic channels passing through cell walls of adjacent plant cells. o Are lines by a plasma membrane o Contain a central structure, the desmotubule. o Serves as a site of cell-‐cell communication Plant Cell Wall • Extracellular • Function o Shape o Support, protection against mechanical abrasion, pathogens and osmotic stress. • Components o Cellulose arranged in microfibrils to provide rigidity o Matrix contains hemicellulose, pectin and glycoproteins. o Matrix keeps the plants hydrates • Assembly of cellulose Synthesis of plant cell walls • Cell walls arise as a cell plate that forms between the plasma membranes of newly formed daughter cells. • The walls of growing cells are primary walls and allow flexibility lacking in the thicker secondary walls of mature cells. CELL BIOL CHAPTER 8 Cytoplasmic Membrane Systems: Structure, function, and membrane trafficking Endomembrane System • Components • Budding and fusion of vesicles from one compartment to next • Tranfer of proteins • Transfer of membrane lipids • Coated vesicles – COP Proteins An overview of the biosynthetic/ secretory pathways
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'